As coal is burned in a power plant or industrial boiler, its noncombustible mineral content ash is partitioned into bottom ash or slag, which remains in the furnace, and fly ash, which
rises with flue gases. Bottom ash is easy to collect since it is removed during routine cleaning of the boilers. The properties of bottom ash make it a good road base and construction material, and,
as such, it can be readily given away or sold. Fly ash, on the other hand, is not so easily disposed of. Most fly ash is captured by pollution control devices before release to the atmosphere
Daniels et al., 2002. The use of fly ash as a material for self-compacting concrete is very beneficial because
the use of fly ash reduces permeability, bleeding, water demand and the heat of hydration. It also improves workability, however strength development is slower. For every ton of cement that is a
manufactured, approximately one ton of carbon dioxide gas, the main greenhouse gas, is released into the environment. From an environmental perspective, one of the benefits of fly ash is that the
replacement of large portions of cement with fly ash serves to reduce CO
2
emissions, thus making concrete an even greener material.
To enhance the properties of fresh and harden concrete, the addition of fly ash can be used as partial replacement of cement. Then, the use of fly ash in concrete is very beneficial because it
is not only economical from cost but it also improves the fresh and hardened properties of concrete. Usually, the addition of fly ash is about 10-35 replacement to the cement can helps to
maintain the viscosity of concrete resulting to in blockage risk and decreases the superplasticizer requirements.
II. LITERATURE REVIEW
Self-compacting concrete is one of innovative concrete by managing a fluid mixture which can reduce the amount of cementitious materials and total volume of concrete required. In
Self-compacting concrete, the fluid mixture can flow under its own weight, completely filling formwork and achieving full compaction in structures even with congested reinforcement. Then,
the use of Self-compacting concrete also can increases the speed of construction and reduces noise. Moreover, in terms of Self-compacting concrete, the cost can be reduced by replacing a
part of the Portland cement, especially if the mineral admixtures are waste or industrial by- product such as fly ash. Fly ash is a by-product of the combustion of pulverized coal in thermal
power plants. Therefore use of fly ash not only provides economical benefits but also reduces heat of hydration Henceforth replacing of Portland cement with fly ash can reduce the production
of CO2 Asha et al, 2013. Self-compacting concrete SCC is a fluid mixture, which is suitable for placing in difficult conditions and in structures with congested reinforcement, without
vibration Bartos, 2000.
Fly Ash is a pozzolanic cement replacement that enhances the performance of concrete by increasing compressive strength, improving workability, durability, long term strength, resistance
to freeze-thaw damage and reduces permeability, efflorescence shrinkage, thermal cracking, alkali silica reaction and sulfate attack in concrete. Basically using fly ash makes better concrete
that is more economical and better for the environment. Fly ash is one of the most extensively used by-product materials. It is an inorganic,
noncombustible, finely divided residue collected or precipitated from the exhaust gases of any industrial furnace. Most of the fly ash particles are solid spheres and some particles, called
cenospheres, are hollow. Also present are plerospheres, which are spheres containing smaller spher
es inside. The particle sizes in fly ash vary from less than 1 μm to more than 100 μm with the typical particle size measuring less than 20 μm. Their surface area is typically 300 to 500
m
2
kg, although some fly ashes can have surface areas as low as 200 m2kg and as high as 700 m2kg. Fly ash is primarily silicate glass containing silica, alumina, iron, and calcium. The
relative density or specific gravity of fly ash generally ranges between 1.9 and 2.8 and the color is generally gray or tans Venkataraju, 2011.
Fly ash improves concrete workability and lower water demand. This is because fly ash pozzoland becomes denser, stronger and generally more durable long terms compared to straight
Portland Cement Concrete mixture. Fly ash particles are spherical and have the same size with Portland cement, therefore the need of water is lower for mixing and placing concrete can be
obtained. The reduction in water leads to improved strength. Because some fly ash contains larger
or less reactive particles than portland cement, significant hydration can continue for six months or longer, leading to much higher ultimate strength than concrete without fly ash.
Fly ash can reduce the permeability and absorption of concrete. By reducing the permeability of chloride ion ingress, corrosion of embedded steel is greatly decreased. Also,
chemical resistance is improved by the reduction of permeability and adsorption. Fly ash is economical because fly ash can substitute Portland cement in concrete mixture and the mixture
with fly ash can increase long term strength and durability.
III. RESEARCH METHODOLOGY
Material
Portland cement concrete is the popular material used in civil engineering projects around the world. Some of the reasons for its use are versatility and adaptability, as evidenced by the
